Liner for tube mills, etc.



1 631 971 June 1927 P. T. LINDHARD LINER FOR TUBE MILLS, ETC

Filed July 11, 1925 at about the rate of wear as that to Patented June 14, 1927. p

UNITEDSTATES PATENT o I 190712 '1'. LINDHABD, 01' BBOOKL YN, NEW YORK, ASSIGNOIB TO 1.

NEW YORK, Y., A

FF ICE.

L. smmrn a 00., or nroaarron or saw was. L

ma non runs MILLS, are. Application fled July 11, 1925. Serial No. 42,888.

Liners of silex, either of shaped blocks of the natural stone or of irregular pieces grouted in, were formerly employed almost exclusivelyfor lining the shells or drums of tube mills and ball mills and were generally satisfactory, except for variations in hardness, which necessitated. renewal of portions of the linin The difiiculty in shaping the blocks 0 natural stone and variatlons in the composite linings, together with the increasing difficulty in securing 'silex-of uniform quality, the scarcityof the supply and the increasing cost have led to many efforts to produce substitutes for the silex liners, cast metal liners being commonly provided and so formed as to prevent the charge of grinding bodies and of the material op-' erated upon from slipping on the inner surface of the liners and, therefore, failing of that degree of constant agitation which is necessary to secure the maximum of efii-- ciency in agiven mill. Most of such cast metal lin'ers, as heretofore produced, quickly become smooth and permit the undesirable, slipping of the charge, or are otherwise sub ect to such wear that the quickly become broken, with the results t at they must be replaced frequently and that there is excessive waste in the form of scrap. The object of this invention is, therefore, to pro-. vide a liner which shall be capable of Ion continued use without becoming smooth and without requiring replacement at such a stage of wear as to involve excessive waste 35 in scrap. In acoordance with the ,invention, the improved liner is made up of longitudinal bars of metal whichyfor convenience in manufacture and in application, are bridged .in series so as to form liner blocks of a size convenient for handling and application, the metal bars being separated (except for such bridges) by spaces which are filled with grout, by which also the bars blocks are secured in'place within the shell or drum.- To secure the most satis-. .factory result, the relative width of the grout filled spaces to the width of the bars 18 de -to some extent by the, size and character of the grinding bodies with which the mill is. charged, the width of the,

at filled spaces be" such as to permit cement grouting, fien set,,to'be worn awayimlg the con'omt action of the grinding 'es and e material being groll nid1 the deeper and harder metal bars are worn away, so that the longitudinally corrugated inner working surface of the liner is main tained throughout its use until the cement filling is almost completely wornfaway and of the metal bars but little is left to become scrapped. The corrugated working surface is provided at the outset by provid ing metal bars of greater depth than the grouting and by sinking the grouting somewhat below the working surface of the bars. Preferably, also, the bars are formed at the outset with somewhat rounded working surfaces, this characteristic being maintained throughout the wearing of the liner so that agitation of the charge is kept up continuously in the operation of the mill and there is practically no slipping of the charge on the liner. The invention will be more fully explained hereinafter with reference to the accompanying drawings in which it is illustrated, and in' which:

Figure I is a' face view of a-series of bars cast in one block.

Figure II is a lon i plane indicated Fi "re I. igure III is a tr Blane indicate igure I. Figure IV is a transverse section showing seyeral blocks or bars applied to the shell ill with the spaces filled with cement tudinal section on the by t e broken line '2' 2' of ansverse section on the d by the broken line 3-3 of of a m grout.

Figure V isva face view showing the placingof joints.

Figure .VIis a vie on a larger scale th illustrating the ma lindrical grinding liner.

Longitudinal bars'a, a, venient for handlin ing a rounded worlfi recessed rear' surface duction, are-united for convenience in cation to the shell able curvature of between successive the blocks in'a mill so as to break" w in transverse section, an that of Figure IV, nner of. coa'ction of cybodies with the improved of a length conand preferably hav ng surface a and a 100 a for economy in proby casting ina block handling and in appliof the mill, with a suitthe block, so as to leave' barslon'gitudinal spaces 6, b, which penetrate the block from face to back and are transverse to the direction of movement of the grinding bodies. The bars are united at intervals by bridges e which,

as shown in Figure II, preferably do not extend to the working of the block, but leave, in

' the front portion of the block, channels which eigtend continuously from end to end. Each outer bar of the block is preferably formed, at its outer side, with spacing projections it so as to provide spaces between the adjacent bars of adjacent blocks.

When the blocks have been placed within the shell 0 of the mill, cement, grout is forced into all of the spaces 6 between the bars and between the blocks and into the recesses c in the blocks of the bars, so that when the cement has set the blocks are securely held in place. In fitting the blocks to the mill one or more bars a may be split ofi as may be desired and wedges may be driven in between adjacent blocks to secure the same if necessary.

Preferably, the bars themselves and the spaces between them are of such widths as may be determined by the size and character of the grinding bodies employed. As shown in Figure VI, the short cylindrical grinding bodies 9' are preferably employed and in that case and as also with grinding bodies of different shape, the bars have a mension of the width somewhat in excess of the greatest digrinding bodies and the spaces between the bars have a width somewhat less than the minimum dimensions of the inding bodies. The purpose of such relation of dimensions is that in the operation of the mill, the relatively softer cement grout shall be worn away by the conjoint action of the grinding bodies and the material being ground at about the same rate as the metal bars a are worn away, whereby the working face of the liner is maintained until the cement grout is practically worn away and the bars are worn to such a thinness'that they become liable to breakage.

In the foregoing description it h s been assumed that the bars a, a, are of 09. metal and the filling in the spaces between such longitudinally corrugated bars of cement grout, but it will be obvious that such invention may be realized with other materials, the bars being of any suitable hard material and the filling between the bars of relatively softer material, whereby the corrugated working surface will be maintained as the liner wears. I claim as my invention? 1. A liner block for tube mills, etc., consaid blocks being provided with intervening spaces between the bars and bridge pieces connecting the bars at intervals along their length, the bridge pieces being recessed at the working face to form with the intervening spaces continuous channels.

3. A liner for tube mills, etc., comprising blocks of longitudinal bars ofmetal with rounded working surfaces, said blocks being provided with intervening spaces and bridge pieces in each block connectin the bars thereof at intervals along their ingth, and a filling of cement grout between the bars ind sunk below the working surface of the ars,

4. A liner for tube'mills, etc, comprisin blocks of longitudinal bars of metal rounded working surfaces having a width as great 'as the minimum dimension of the grinding bodies and not greater than the maximum dimension thereof, and bridge pieces connecting the bars at intervals along their length, and a filling of cement grout between thebars and sunk below 'the working surface of the bars.

This specification signed this 9th day of July, A. n. 1925.

' POVL T. LINDHABD. 

